Field of the Invention
The present invention relates to an impeller for a revolver cylinder and, more particularly, to a cylinder impeller comprising two parts that moves therebetween.
Description of Related Art
Revolvers are defined as revolving cylinder firearms containing multiple chambers where ammunition cartridges are housed. When a shot is fired the cylinder revolves to an angle corresponding to the distance between two consecutive chambers in order to align a new chamber (with new ammunition cartridge) to the gun's barrel.
The configuration adopted by revolver manufacturers, especially double-action revolvers, comprises of a cylinder impeller pulled by the gun's trigger. In particular, and as shown in FIG. 1, said impeller 101 has basically the shape of a fixed length rigid rod and comprises articulation and actuation means at each one of its ends. Specifically in the bottom end, this cylinder impeller is hinged, by means of a pin 102, to the trigger 103. The cylinder impeller upper end acts on the named extractor teeth 104, equal in number to the number of the cylinder chambers 106, disposed on the top of the extractor, integral part of the cylinder set 105. The cylinder impeller actuation on these teeth 104, each time the trigger is pulled, changes the cylinder angular position and positions a new chamber relative to the barrel.
The cylinder impeller functions are basically two:                To lead (by revolving) the cylinder to the new position, ensuring that a new chamber, previously loaded with ammunition, is aligned to the gun's barrel; and        to lock in keyway the cylinder in the new position, i.e. to keep it aligned with the gun's barrel and without side movements at the time the gun is fired.        
Although this operation mechanism has been used for long time, it is not free from drawbacks. To properly secure the above mentioned performances, the cylinder impeller must act likewise on each extractor teeth. The number of these teeth can reach ten depending on the revolver model.
It is the first drawback of the current system to ensure that each tooth is in the same position at the time of positioning and keying the cylinder. To achieve this, it is necessary to work with very strict machining tolerances, increasing the cost of the process, or to set up, for said teeth, manual adjustment levels. This manual adjustment, which must be properly done in each one of the teeth, also makes more expensive the process, besides causing, with some frequency, exceeding adjustment problems. The removal of material more than what is necessary disables the extractor, since it creates air-gaps in the system.